1. Field of the Invention
This invention relates to growing semiconductor layers and devices that incorporate such layers.
2. Description of the Related Art
Epitaxial methods grow layers by depositing atoms on a growth surface and allowing the deposited atoms to find stable attachment points by diffusing along the surface. Thus, epitaxial methods use a crystalline structure of an initial growth surface to orient growth of the crystalline layer being grown. While epitaxial methods produce relatively smooth layers, the final layers are not smooth on atomic-scales.
Rather epitaxially grown layers have various types of roughness, which are shown in FIG. 1. The first type of roughness is islands 10 on the growth surface 12. Deposition of an atom on a flat portion of the growth surface 12 forms such an island 10. The second type of roughness is a hole 14 in the growth surface. Evaporation of a deposited atom from a flat portion of the growth surface 12 forms such a hole 14. The third type of roughness is a step 16 on the growth surface 12. Cutting an initial growth surface typically causes a misalignment with underlying microscopic lattice planes and such misalignments produce steps 12. These types of roughness at atomic-scales are not completely removed by epitaxial growth.